The revised syllabus for Advanced Level English (ENG 0730) in Cameroon prioritizes the development of communicative competence through effective instruction in English phonology, as outlined in the "Speech Work" component. However, a critical evaluation of Mastering English: High School reveals significant misalignments with the principles of the Competence-Based Approach (CBA) and the unique phonological challenges faced by Cameroonian learners. This study examines the breadth and depth of phonological topics in the textbook, the accuracy of phonemic representation, the contextual relevance of vocabulary, and the integration of communicative practice opportunities. Findings indicate that while some lessons provide basic coverage of segmental features, there are substantial gaps in the treatment of suprasegmental aspects such as stress, rhythm, and intonation, inaccuracies in phonemic descriptions, and a lack of learner-centered, communicative activities. These shortcomings undermine the textbook's capacity to foster the development of communicative competence among learners. The study proposes targeted revisions of the textbook, including the integration of contextually relevant vocabulary, task-based activities, and differentiated instruction. Additionally, teacher professional development and curriculum alignment with the GCE Advanced Level English syllabus are recommended to enhance the quality and relevance of phonological instruction. These measures aim to equip Cameroonian learners with the phonological skills necessary for intelligible communication in academic and professional contexts.